[PATCH 0/3] sched, x86, arm64: PREEMPT_RT, FPU and preemption

Valentin Schneider valentin.schneider at arm.com
Thu Jul 22 10:51:54 PDT 2021


Hi folks,

This stems from some more v5.13-rt1 breakage on arm64. This time per-CPU access
safety isn't sufficient, we really need to keep preemption disabled.

In a happy accident I stumbled on

  cba08c5dc6dc ("x86/fpu: Make kernel FPU protection RT friendly")

so I packaged what was done there into some common helpers and plastered them
over the problematic areas.

Cheers,
Valentin

Valentin Schneider (3):
  sched/preempt: Introduce preempt_{enable, disable}_bh()
  x86/fpu: Make FPU protection reuse common helper
  arm64/fpsimd: Fix FPSIMD context handling vs PREEMPT_RT

 arch/arm64/kernel/fpsimd.c     |  6 ++++--
 arch/x86/include/asm/fpu/api.h | 19 ++-----------------
 include/linux/bottom_half.h    | 26 ++++++++++++++++++++++++++
 3 files changed, 32 insertions(+), 19 deletions(-)

--
2.25.1




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